Insulator bushing and means for supporting cores or baffles therein



Aug. 27, 1929. A. o. AUSTIN '7 1,726,095

INSULATOR BUSHING AND MEANS FOR SUPPORTING CORES' OR BAFFLES THEREIN Filed Aug. 11, 1924 "INVEWTOR ATTORNEY 3 .5 nvhichshall have improved means for sup- "Patented Aug. 2 7, 1929, 2

NITED STATES .;.PA T..-ENT. oFFIc-E'. Y

. nn'rnun o. "Aus'rm, or nnnnnn'rom onro, assrenon, BY mnsnn assiennnn'rs'gro .srnn onro BRAss company, or MANSFIELD, ,onro; A conronarronon NEW am SEY.

msnmron nusn'me am) ,mnsnsron surron rriqe cormsore-Bananas 'r'nmmm.

Application filed August 11, 152 17 seria no, 731,502.

I This invention relates to insulator bushings for high potential conductors andhas tor its object the provision of a bushing of improved construction and operation and :Qporting internal baffles or cores therein.

vention. i

-1 he'inv'ention is ex emplified in the combination and arrangement of parts shown in "In'the form shown, thetwisted conductor may have suflicient resiliency to provide for ..difierences in expansion between the conduc tor and the dielectric shells, or itmay beconstructions are involved, it is not necessary to support the baffles 19 and 20 except from the main outenshell members The bafiles' the accompanying drawings and described '19 and 20v are held together. by a joint 21 in the following specification and it is more Fig. I is an elevation w'i-th partsin Section showing one embodimentof'the present 1n- Fig. 2 is a sectionon line of Fig 1.

In high voltage -bushings where it is desiredto have little or no surface charg-in current until a ver high ..volta'geiis rrgtche it is highly desirale'to constructthe'hushinns ,in two arts usin an internal electrostatioscreen to suppress charging current,

' tending to start from the flange. Bushings of this type are usually constructed with two dielectric shells which' form thenuter conof this kindis to-support the-bellies and not v Fig. 1 shows a type oi construe is very effective for overcom ng these iilfiitour and a center nest of names with-the intervening space'between bafiies andmter shells filled with insulating oil-or com pound.

One of the most difiicultproblemsqn bushings destroy theeflfective tightness :of the outer chamber formed by the shells;

ion which :ing at relatively low cost. 'Figl-hows one forinof the invention and Fig. 2 shows ase'c-.

, .tion'on line '2 -2 of Fig. 1.

' sired; In Fig.

- It is evident that the bushing may have weather sheds 'orflanges at either {or both ends or may be entirely smooth, depending upon portions are made tight by a gasket .14 which is clamped tightlyby the bolts 15. -A 'conductorlfi extends through the center of the bushing and terminates in the'mcmbers 17 and 18.

the use for {which the bushing is dc- 1 the bushing consists of an i upper dielectric member 10, a lower -dielectric member 11- assembled or attached to holdi ing flanges 12 and 13 respectively... The twovhich maybe a suitable cement or cushionprior Patent No. 1,284,975. Where a cushloning material such as. cork is used it is assembled so as to be slack. If either ofthe inginaterialsuch as cork squeezed into the- 'spacebetween the. two members." Where;

generally advisable to use a varnish which surfaces when dry or'when baked. In order t6. preventichja rging current flowing over the surfaces of the dielectric shells 10 and 11 from the metallic holding members 12 and 13,-it is usually desirable to insert an electrostatic screen 22. In order to'be effective, this screen must have considerable capacitancebetwe'en it and the metallicjniembers 12 and 13 or be indirect contact with themi .In Fig. 1, contac't between the electrofstatic shield 22. and the holding member 13 is made through a spring or lead 23 which .is inserted in the gasket 14:. This contact islna'de'between'the member 23 and "a thin metallic idaih 2 immediately on the inside ofthe shell. The. metallic dam 24 makes Contact either through the bolt 15 or by havdngthe end turned under the lower half of the-gasket. The spring or contact member '23 being thinmay be readily clamped in the gasket, which is preferably made in two 'or three layers, without destroying the tight ness of the 'ointl' If the electrostatic screen 2235 used to hold vthe'center bafiies ;as in somecases, a rather heavy metallic member must'be need which is inserted inthe joint ..or by attaching directly toa flange or sleeve. This tends to subject the members of the shell -to mechanical stress due to difier'ent expansion and tends to destroy the tightness of the joint-J." a.

In the construction shown, it'is'possible to clamp the dielectric-members directly together ith only a small gasket-of yielding will cause the cork to adhere firmly to the 1 Where: the. holding member 25 has practifbir for' a givenlength b low the flange material intervening. The. construction adopted also; makes 1t unnecessary, to use an intervening sleeve 'for holding purposes or- -to" project below (the oil level. B By the'elimination 5 of the intervening sleeve the obj ec- "-"by'-t he-statio screen 22. 7 Since jthed'ielectric yie1d ing" material: such as cork,, mineral felt' or rollsof varnished cambrio or tapej or even wo'oden' spacers-11 Thematerial' 25. usedfor Shelli-"These spacers-Tare .preferably of a holding, "-sho uld' have vents '26 as shown in ing with .oil or ;compound -and a'ls(), -pe rmits the circulation'of the oil "so as to-maintain-a fairly'uniform temperaf' means to the 's 'ells or to the bafilejmember "1.19. Since the members 19 'and 20 are; held together mechanically, it is'evident that the holding'f'member 25 maybe applied between the shell and the-member 20 in placeof the 1 tu're' on-all parts of the-bushingand' to pro vide for carrying'away' the heat" generated win the'c'on'duotonj I Y j. The spacing .or holding members 25 may be attachedbvarnish or .'-oth'er'.- suitable mem'ber 19 bysuitably forming-the parts.

callythe same -insulating propertiesas th'e' filling 'oil or compound, the distribution'off'f ber's together toform a; c osed'ca'sing, a ey- 2 stress. and performance of the bushingwill poundin the s'paces27, 28 and 29. The ce? .:not be afiect'edand. the performance will be equivalent to that-where ne i ielding member is'used. x

The constructionresults in a bushing hav- ';-ing relatively light weight, high .dieleotrie strength-, {freedom from static 'or surface charging current and one which may be readily assembled or disassembled should a part become accidentally 'orotherwise damaged.

:The construction issuch thatthe'dielectrio 'stressjis taken up 'not only by the dielectric J members 19 and 20 but by the oil or com mentor 1 holding means 21, between" the baflles is" rovidedwith vents30 shown in Fig.'2.- Since it isnot necessary tosupport thelba'iiie system b. thenc'enterconductor, a-

" flexible conductor aving resiliency may be used which avoids the necessity of expansion joints at. the. upper end,- thereby slmplifying Y the construction, Vents 31 are provided-to I claimz f I Lmeinbers IOrHbafiIesQIQ-and=20-areIlikely to 5 have considerable weight and may be frag- ,ile, su'itable"xneailsilinust be gprovided for" holding-them inplac'e 'lnjorder to hold the bafilesrfor cylindrical. dielectrical inemm'aterial within said casing,

low casin relieve the bushin gfrom internal expansion; No expansion chamber is necessary, owing to the "continuous-upper shell which. permits Ttheuseof an air s ace in the up in: section V withoutvafl'ecting'tii -ti on due to different expansioni is notton'ly i removed but a "greater amount ofsurface I insulation is provided for the lower -'-memwithout danger; of static discharge over the lower end'ofthe btishing. asthiis. i'sprevented mg. 7 V y- 1 Y We v -An expansionchamb'erfmay 0t 'cou e, be

used,"as is: common practice;with oiloriiom pound filled. types; -Entfanceinay"also,--be made -through the-joi n t' fOr'controllingthe' heightfefythe oiloncompoundf ,1'}.e 75

' 1-: u at r u h ieomi r ai w of shell. members, means $61 clamping- :Qshell members together to arm a closed cas i 1mg, a cylindrical 'bafiie arranged within3sa-id-80 cas ng; and oven-lapping the joint between g said shell members; andf'spacersinterposed bafile's' and the members' composing the outer f betweenjsaidl 'baflle: and the interior of said shell members "tosupport said b'afiie -Within said casing, said spacersbeing arranged to 8 elongated; casing 0t dielectric I material 11, 'pl urality.fof concentrically arranged-joy indrical bafiles-within said' casing,,means'cbnj nec'ting" adjaeent facesf'of said baflles but, i providingcirculation-openingstherebetween.

1. an'dfspacers for. supporting theoutermO'Stone T of said bafiieslfrom-the inner'surfajce of said j casing said spaeers being arranged in circiimferentially spaced relation to 'one another to provideropeningslfor the icirculation fo'f. I

3; An insulator bushng comprising-apam of shell members havingopen ends arranged to re 'ster with one another said shell mem- 'bers' eing' tapered inwardly from -said open 'ends, means for elampin" .said'shellmem- 165 lindrical b'afile'dis osed within said casing and over-lappingt e oint between said shell members, packing materialifor supporting I said bafile within said casing and providing openings for the. circulation of -material within'said-casing; a second-cylindricalbafile arranged within said first'bafii'e inspaced relation thereto, and having one end" thereof projeeting'beyond'the end, of said' first'named bafiie and means for sulgforting' said's'econdr 'bafiie" from said first{ ba e 1 'nsul tor bushing comprising an 5. An insulatorbushingfcomprising a holv of "dielectric -material'-, a. hollow '12s cylindrica bafile of dielectricjmaterial dis-- posed within said casing means for supporting said bafile from the interior of said casing and a flux screen of conducting material supported on the outer face of said baflie.

6. An insulator bushing comprising a pair of dielectric shell members, means for clamping said shell members together to form a closed casing, a cylindrical batHe having supporting bearings upon the inner surface of said casing and arranged in over-lapping relation to the joint between said shell mem-. bers, a flux screen of conducting material supported on the outer surface of said baflle and means extending through the joint between said shell members for making electrical connection with said flux screen.

- 7. An insulator bushing comprising a pair of shell members having open ends arranged to register with one another, a flange secured tothe outer face of one of said shell membersadjacent its open end, means for clamping said shell members together to form a closed casing, a cylindrical battle of dielectric material arranged within said casing and having supporting bearings on the inner surfaces of said shell members, a cylindrical flux screen surrounding said baflle and supported thereby and means extending through the joint between said shell members for forming an electrical connection with said flange and flux screen.

8. An insulator bushingcomprising a pair of dielectric shell members having open ends arranged -to register with one another to form a casing, metallic flanges secured to saidshells adjacent said open ends, means for clamping said flanges together to hold the ends of said shells in abutting relation,

packing material interposed between said ends, a flux screen arranged within said caspacket joint between said abutting ends.

9.. An insulator bushing comprising a pair of dielectric shell members having open ends, means for clamping said shell members to one another to form a closed casing, a cylindrical baflle of dielectric material arranged within said casing and having the ends thereof seated respectively on .the interiors of said shell, members, a flux screen surrounding said batlle and and a covering of dielectric material for the edge of said screen.

10. An insulator bushing comprising a pair of dielectric shell members having open ends arranged to register with one another, a metallic flange secured to one of said shell members, means for clamping said shell members together to form a closed casing, a conductor extending centrally through said casing, a cylindrical batlle of dielectric material having opposite ends thereof seated upon the interior of said shell members respectively. a second bafile within said first ARTHUR o. AUSTIN.

.50v supported thereby 

